Reed Canary Grass (Phalaris arundinacea L.) is perhaps the worst
invasive species in Wisconsin, to date. It forms dense, nearly
pure stands that displace all other species from large areas of
wetlands, especially sedge meadows. Colonizing plants soon spread by
rhizomes to form ever larger clones. When in
flower, the branches of the inflorescences tend to spread
out and may be any shade of color between medium purple and bright
green. After pollination occurs (early June) the branches close back
on the central axis to assume the appearance
of a spike and the flowers eventually turn to a light tan color
and may remain on the stems well into the fall and winter. Leaves often
exceed 1 cm in width, broader than virtually all other grasses in our
wetlands, except for common reed grass (Phragmites australis).

Control of Phalaris is extremely difficult and there are few
if any examples of longterm success in heavily infested sites in disturbed
landscapes. Although the plants can be killed by a variety of methods,
vigorous re-invasion is common and none of our native species appear
to be capable of competing with Phalaris in a disturbed landscape.
Wetlands receiving a large share of water from ground water are more
resistant to invasion.

Recommendations for control of Phalaris are similar to those
for Phragmites australis. As in all invasive plant control problems,
the best return for limited resources rests in prioritization of sites,
regular monitoring for early discovery and removal, and vigilance thereafter.
Because Phalaris does not usually produce large numbers of new
seedlings, one of the most effective means for control is to monitor
susceptible areas and destroy any new plants before they can expand
vegetatively. This is especially true in cases where wetlands
have been disturbed, or in recently created or restored wetlands.
When an established wetland vegetation of native plants is in place,
the incidence of colonization by Phalaris is much reduced and
expansion of the clones is much slower. Application of herbicides
can be effective in killing established populations of Phalaris,
but may also kill other, more desirable plants in the area and if the
site is not monitored thereafter, any surviving plants can quickly reoccupy
the area. Expectations are low for restoring large, long-established
populations in disturbed landscapes.